Fusible link and strut



L. M. LEWIS.

FUSIBLE LINK AND STRUT. APPLICATIONv HLED'MFLM,1919.l

i Patented May 11, 1920.

NVENTOR WITNESS ATTORNEYS UNITED STATES PATENT OFFICE.

LEROYv M.k LEWIS, or PHILADEILISHIA, PENNSYLVANIA.

FUSIBLE LINK AND sTRUT.

Application le'd April 24,

To all whom, t may concern: v

Be it known that LLEROY M; Lnwls, a citizen of the United States, a resident of the city of Philadelphia, county of Phila'- delphia, and State of Pennsylvanizuf have inventedv certain newl and useful Improvements in Fusible Links and Struts, of which the following is a specification, reference being had' tol the accompanying drawing, forming a partVV hereof.' y

My' invention relatesto a fusible'lin'k or struty of the type used in fire extinguishing systems and devices wherein it is ,desiredto hold certain parts of the mechanism to which thev links or vstruts are applied in assembled relation until sufficient heat beL comes present in the vicinity of the contrivance to cause the link or strut components to become separated by theI fusing ori melting ofthe fusible binding materialnor- Ymally uniting' the component parts tovent any creeping' for cold-flow7 action which would interfere with' the proper functioning of the-device.

further object is to provide means in y one of the assembled parts to prevent its displacement or separation from the other parts during the assembling thereof and to therefore insure against a premature opera'- tion of the device b v reason of suchA displacement or omission of such part.

A still further object is vto also provide means which is of' utility to indicate upon inspection the presence lof an essential part of the assembly and hence the operative'- ness of the device.

Other objects of my invention will more fullyappear from the following` specifica# tion and in the accompanying' drawing.

It has been found that links o'r struts-of thetype mentioned frequently fail or op; crate prematurely, the'cause for this usually Specification of- Letters Patent. Patented ljIay 11, 1920.

191e'. Y semi No. 292,409;

being that in assembling the parts the workman at the4 factory may permit the key, that is interposed; betweenl the plates, to slide out from therebetween and asthe solder or fusible material fills the space that would otherwise be occupied by the key as well' as protruding more or less from the edges.l of the plates and the key socket formed between said plates, there is nothing; toindicatefwhether or not a key is contained within the socket and consequently an omission of a key in this manner` renders a link or strut useless. Such device may be subjected'to careful and proper inspection yet since the fusible material completely hides the space that would be occupied by thekey it is'usually assumed that the key is present and is covered by said fusible material andi the 'defective linkL or strut passes' inspection without any detection of its actual defect.I If, on the other hand, a key, is in fact,l

included or contained withinr the socket, provided between the plates, at the' time of the assembling thereof itfrequently occurs that the solder or fusible material is improperly applied so that it does not'efl'ec# tively seal the ends of the socket' at the ends of' the key and it is possible, vat any time, forthe key to become displaced or entirely' separated from the plates, while in transit or lying in storage, without its being observed land when the link or'strut is subsequently'atta'ched to a sprinkler head1 it will' notv be able to withstand or sustainv the strains placedi upon. it bythe waterv y omission. of such key 'and conseduently it will] prematurely operate, a conditionY which I is very annoying and objectionable aswell as causing 'considerable damage. to goods`l with which the water comes in contact.v

It has also been: discovered that even though a link or strut ofi the type mentioned becompletelyassembl'ed and properly mounted in a sprinkler head certain conditions may arise or occur where the fusible material in the ends ofthe socket may become detached 'or fall out by the vibra tions of the pipes; such as, water ham*- me'rs, chatterings and the like whereby the" key may become' `gradually displaced and finally separated from therest ofthe' linkfor strut structure as a result' of which the link or strut will prematurely operate.

My" invention', therefore, involves' the idea of constructing a fusible link or strut with means adapted to avoid the conditions mentioned above and which will respond only in the presence of heat suiiicient to fuse the fusible material and to properly operate at Vthe time and in the manner in which it is ble link involving my invention;

Fig. 2 is a view in vertical elevation thereof;

Fig. 3 is another view in vertical elevation thereof transverse to that shown in Fi .2;

ig. et is a vertical sectional view taken on line 4 4 of Fig. 2; Y y

Fig. V5 is a vertical sectional viewY taken on line 5-5 of Fig. 2; Y Fig. 6 is a view similar to that shown in Fig. 4 with the parts in operating and sepa rating position;`

Fig. 7 is a horizontal sectional view taken on line 7-7 of Fig. 2,

Fig. 8 is a horizontal sectional view taken on line 8--8 of Fig. 3;

Fig. 9 is a perspective view of a detail, and

Fig. 10 is a view similar to that shown in Fig. 4c with my invention applied to a fusible strut.

The link or strut forming the subject-matter of the present invention may be said to embody three elements, to wit, two preferably substantially flat members or plates adapted to be connected together by their adj acent faces with fusible material or solder and a pressure sustaining or restraining member or key interposed between said plates and acting to normally prevent relative movement of said plates until the'fusible material has become sufficiently fused to permit said key to separate said plates.

s illustrated, my improved link or strut comprises a pair of substantially rectangular flat'plates land 2 each respectively provided near'one end thereof with the apertures 3 and 4L and at the other end thereof with notches 5 and 6. These plates are adapted to be placed together face to face and with the apertured end of one adjacent the notched end of the other, so that the apertured ends extend in opposite directions, with the aperture of one plate registering with the notch of the other plate. The apertures 3 and 4 are adapted to receive the parts to be connected to the link when the latter is assembled for operation, such as the projecting lever'arms a and b of the members.

of a two-part toggle type of strut or lever arrangement in a sprinkler head.

The plates 1 and 2 may be provided with substantially rectangular openings 7 and 8, one of such openings being provided in each of said plates' and located substantially midway between the longitudinal center-lines of said plates and a lateral edge. thereof.

The plates are also further provided with laterally bent portions 9 and 1() which are disposed substantially in horizontal aline ment with the respective openings 7 and 8 and extending between said openings to a point near the opposite lateral edges of said plates, said portions being preferably in the form of a right angle to provide, within the angle of the same, shoulders 11 and 12 adapted to inclose therebetween, when the plates are joined together, a space of substantially rectangular shane in cross section, which may be termed a key-socket, and which is disposed at an inclination or acute angle to the planes of the plates 1 and 2.

The key 13 is adapted to be located in said v key-socket with the edges 14 and 15 of the key adapted to bear respectively against the internal shoulders 11 and l2 in order that the forces tending to 'longitudinally move the plates 1 and 2 with respect to each other will be sustained by said key, a small component of such force only being effective to separate the plates when the fusible material is fused to cause the key to rock or turn in a counter-clockwise direction, as viewed in Figs. 3 to 6 inclusive of the drawing, for the purpose of separating said plates. As the plates become thus separated the relative positions taken by the parts, includin g the key, are believed. to be thatr shown in Fig. 6 inwhich the key is shown turned about a horizontal axis and the plates'separated from each other just prior to their being further separated by the outward movement of the lever-arms c and b of the Ysprinkler head structure. Y

lt will be observed from the illustration 3 and 4, as well as the bends 9 and 10 are arranged in staggered relation, so that the aperture 3 of one plate is disposed opposite the end of the laterally bent portion 10 of the other plate, while the aperture dof the latter plate is located opposite the end of the laterally bent portion 9 of the first mentioned plate with only substantially about one-half of the length of the laterally bent portions 9 and 10 located opposite each other at the central portions of the plates, the space inclosed by these portions forming the key-socket proper, the purpose of this construction being hereinafter more fully disclosed.

The key 13 referred to above comprises a body portion 16 of a substantially Hat rectangular shape and is provided at the ends of said body portion with laterally bent flanges 17 and 18 extending in opposite directions, The body portion of the key is recesso or'21, provided in the internal faces of the laterally bent portions 9 and 10 and located on the longitudinal center lines of said plates, for the purpose of maintaining said key in said key-socket from displacement `relative to the plates 1 and 2 and the parts formed thereon.

The key is lof such a length that the flanges 17 and 18 respectively project substantially centrally through the openings 7 and S so that the faces of the flanges 17 and 18 are'substantially equally distant from the respective edges 22 and 23 of the openings 7 and 8.

1n order that the plates'l and 2 shall not be too much weakened by providing them with the openings 7 and 8, the latter are cut as short as is 'possible and in order that the flanges 17 and 18 may be adapted to operate through these' openings Ywithout interference the flanges 17 and. 18 are especially formed in the shape of right angle triangles with the edges 24 and 25 thereof lying respectively in the same planes as the edges V1l and of the body portion of the key, and the other, or hypotenuse edges, 26 and 27 of the flangesY inclined at an acute angle to the edges 24 and 25, this inclination being given to these edges for the purpose of preventing the flanges from contacting with or jamvming against'the ends 2S and 29 of the openings 7 and 8 during. the rocking or turningl movement of the key within the key' socket upon tne parting of the pla-tes, as is more clearly shown in F 6 ofthe drawing. lf these flanges were of rectangular form or even of the forni of isosceles triangles, it may be seen that in such case the flanges would contact with the ends 28 and Y 29 of the openings and would, at least, im-

pede and interfere with Ithe proper movement of the key relative to said plates.

The flanges 17 and 1S are also of such a length hat the same shall project a substantial di rance beyond the outside faces of the plates 1 and 2 so that whenthe openings 7 and 8 are completely filled with fusible material the ends of the key shallproject eX- teriorly of said material and are easily visiv ble upon mere inspection thus indicating the presence of a key in the link assembly.

From the above it may be seen that the structure described andA shown comprises a special form of the key and is of particular utility for the reason that when such key is 'placed within the key-socket and the plates are brought together and soldered with fusible material, in a manner that is v: ll-known, the key is virtually locked into place, first, by reason of the lateral depres- Asion'19 fitting in one of the recesses 20 or 21,

whichl operate to prevent any longitudinal' movement of thekey inI its socket and, secondly, if such key were possibly able to move, the flanges 17 and 1S would prevent the key from becoming separated from the assembly, by reason of the flanges eontacting with either of the edges 22 or 23 of the openings 7 and 8.- lt is intended, however, that the flanges 17 and 18 shall be normally maintained in mid-position in each of said openings and equally spaced away from the edgesI thereof. T he )uraose for this is that in the event that the flanges should be bent in either direction, whether due to accidental causes or through the intentions of a person desiring to prevent theY operation of the sprinkler head, the width of the openings 7 and 8 is suoli, notwithstanding the fact that the flanges might beso bent, as to permit such flanges to freely pass through said openings whenever the link operates, as is clearly shown in F ig. (l of the drawing. Another feature of the invention is that by making the flanges of sufficient length to project a substantial distance beyond the surface of the fusible material in the openings 7 and 8, the flanges serve as visible means for indicating the presence of the key in the assembly, so that it can be made lcertain upon mere inspection that the link is not defective.

1n the usual form of link using a key of uniform dimensions when the plates are brought together in the factory and the key is placed therebetween, it often occurs that the key slides out of the socket unobserved by the workman and when the solder is later applied, the same not only is applied to the adjacent faces of the plates but also fills the ends of the sockets, thereby hiding from view the interior thereofA and giving the appearance that the link has been properly assembled and, consequently, the

link passes inspection a perfect article;

My invention, therefore, comprehends the idea-of overcoming this disadvantage by providing the key with projecting flanges with the ends thereof open to view to such an extent that the same cannot be completely covered and hidden `by the fusible material, thereby serving as an absolute means of indication of the presence of such key in its socket. 1f, upon inspection, it is found that a fusible link vlacks these projecting flanges there is only one conclusion to make, namely, that the key is omitted and, therefore, the strut or link is defective for the uses intended therefor, the same bcing accordingly discarded with an avoidance of the objections and annoyances sought to be overcome.

Furthermore, in theV old structures, even though the same may have been properly solder or fusible material, upon which' dependence is placed for maintaining the key within the socket, may not be improperly applied and, therefore, while the link is in transit or is in the process of being assemf bled in a lire extinguishing system or even after it has become so assembled, whether due to the vibrations of the pipes or to other similar causes, it frequently occurs that relative movement between the key and the Vplates is produced with the result of dis. placing the saine and separating the key from the rest of the link, whereby premature operation occurs. With the form of key made in accordance with the present invention this is impossible, first, due to the locking action of the depression 19 with the recesses 20 or 21 and secondly, due to the fact that the flanges 1T land 18 would prevent the key from falling out of its socket, even though it were able to move in its socket, by reason of the contact lof said flanges with the edges of the openingsV 7 or 8, thereby absolutely insuring against the separation of the key from the plates until the time for the fusing or melting of the fusible material upon the occurrence of a fire or other similar conditions.

In the drawing is shown in Figs. l to 6 inclusive a preferred application of my invention to a link. The invention, however, may be applied to a strut and for the purpose of illustrating such adaptation I have shown in Fig. 10 a strut structure which in every respect is similar to the link structure hereinbefore described with the exception that the plate ends corresponding to those provided with apertures 3 and l in the link structure are here provided with notches 5 and 6', so that the forces instead of being applied in a direction to pull the plates longitudinally apart, are applied in a direction to compress the strut structure so that the thrust is received against the edges la and 15 of the key body in the same manner as in the preferred form described above. It may be observed, however, that the notches 5 and 6 are considerably longer than the notches 5 and 6 of the preferred form for the purpose of permitting unrestricted movement of the lever-arms of a sprinkler head lever device, tending to compress the parts of the strut.

In operation the link is usually attached to the lever-arms a and of a toggle type of structure used in a sprinkler head and in the preferred form these levers tend to separate from each other, said separation being restrained by the link connected therebetween. Upon the occurrence of a fire in the vicinity of a sprinkler head carrying one of these links, the heat of the fire will melt or fuse the fusible material between the plates 1 and V2 and permit a movement of the plates relative'to cach other. Such movenient tends to be longitudinally ofthe plates,

and inasmuch as the plates are no longer held by the fusible material, the same will be caused to act by way of the bent por-- tions 9 and l0 upon the key 13 rocking or turning the same about its axis, such action operating to separate the plates laterally for a substantial distance so that contact of any water that may issue from the sprinkler head with the plates and the fusible material remaining thereon will have no effect in freezing said plates together again. The plates will accordingly be separated by the lever-arms a and b.

During this operation, the key, as aforesaid, rotates about its axis to separate the plates and the flanges thereof are carried through their respective openings and 8 irrespective of whether or not the flanges have beenvbent or otherwise deformed.

In the strut structure shown in Fig. 10 the lever-arms are so mounted as to tend to move toward each other, instead of separating from each other as in the preferred form of the device described above. The operation of the plates of the strut device and the key therein, is, however, the same in all respects to the operation of the parts of the link structure, except that the plates move longitudinally in the opposite direc tions.

While l have herein disclosed and shown in the drawing an embodiment of my invention as applied to fusible links and struts, it is to be understood that the invention is not to be limited to the particular details described and shown but that other and equivalent devices maybe utilized and may also be applied in other relations such as in-connection with automatic fire doors, lire alarms and other devices wherein fusible links or struts are of utility, without, in any way, departing from the spirit of my invention and the scope of the appended claims.

Having thus described my invention what l claim and desire to secure by Letters Patent is:

1. 1n a fusible link or strut comprising a pair of plates provided with socket portions, the combination of a flat key member located between said plates and in said socket portions and projections on said key member at the ends thereof projecting in staggered openings provided in said plates and out of contact with said plates but adapted to normally maintain said key in said socket portions.

2. In a fusible link or struteomprising a pair of plates provided with socket por'- tions, the combination of a key member located between said plates and in said socket portions and projections on the ends of said key member spaced from and out of contact with said plates to normally maintain said key vmember in said socket portions and to visibly indicate the presence of said key in said socket portions.

3. In a fusible link or strut comprising a pair of plates provided with socket portions, the combination of a key member located between said plates and in said socket portions and lateral extensions provided at the ends of said key member and spaced from the edge of said plates.

4. In a fusible link or strut comprising a pair of plates provided with socket portions, the combination of a key member located between said plates and in said socket portions and oppositely extending lateral projections integrally formed at the ends of said key member.

5. In a fusible link or strut comprising a pair of plates adapted to be connected by fusible solder and socket members adapted to define a socket therebetween, the combination of a key located in said socket and in inclined relation to said plates, said plates being provided with staggered open ings, and lateral flanges at the ends of said L key projecting through said openings a substantial distance whereby the presence of said key in said socket is indicated.

6. In a fusible link or strut comprising a pair of plates adapted to be connected by fusing solder and socket members on said plates adapted to define a socket therebetween, the combination of a key located in said socket, said plates being provided with staggered openings, and laterally extending flanges at the ends of said key projecting through said openings whereby the presence of said key in said socket is visibly indicated, said flanges provided with tapered portions thereby providing clearance between said flanges and the ends of said openings during the turning of said key upon the parting of said plates.

7 A key for fusible links and struts comprising a body portion of substantially rectangular shape and integral laterally extending triangular end portions.

8. A key for` fusible links and struts com-v prising a flat vbody portion of substantially rectangular form and laterally extending Hat integral triangular end portions, said end portions having an edge thereof in a plane at right angles to said body portion.

9. In a fusible link or strut comprising a' pair of plates provided with socket por tions, the combination of a key member located between said plates in said socket portions, having its ends bent in opposite directions, extending through openings provided in said plates and out of contact with said plates.

10. In a fusible link or strut comprising a pair of plates provided with deflected portions, the combination of a key member located between said plates in said deflected portions and transversely of the line of strain thereof, said key member having its ends bent in opposite directions, lying in planes substantially at right angles to the line of strain and extending through openings provided in said plates in spaced relation thereto.

11. In a fusible link or strut comprising a pair of plates provided with socket portions, the combination of a key member located between said plates in said socket portions, having its ends bent in opposite directions, of substantially triangular shape, extending through openings provided in said plates and out of contact therewith.

12. In a fusible link or strut comprising a pair of plates provided with deflected por tions, the combination of a key member lo cated between said plates in said deflected portions and transversely of the line of strain thereof, said key member having its ends bent in opposite directions, of substantially triangular shape, lying in planes substantially at right angles to the line of strain and extending through openings provided in said plates in spaced relation thereto.

13. In a fusible link or strut comprising a pair of plates provided with socket portions, the combination of a key member located between said plates, in said socket portions, having its ends bent in opposite directions, of right triangular shape, extending through openings provided in said plates and out of contact therewith,`said bent ends having an edge thereof ina plane containing an ed e of the key portion located in said de ected portions.

14C. In a fusible link or strut comprising a pair of plates provided with deflected portions, the combination of a key member located between said plates in said portions and transversely of the line of strain, said key member having its ends bent in opposite directions and of right triangular shape, lying in planes substantially at right angles to the line of strain and extending through openings provided in said plates in spaced relation thereto, said bent ends having an edge thereof in a plane containing an edge of the key portion located in said deflected portions.

In witness whereof I hereunto set my hand this 23rd day of April, 1919.

LEROY M. LEWIS. 

